DESCRIPTION: (Applicant's Description) Advances in youth smoking prevention that were realized in the 1980's are beginning to erode (Johnston, 1997). In order to prevent children and adolescents from becoming regular smokers we need to better understand the psychosocial factors that place young people at risk for tobacco use initiation and progression. Using a large-scale longitudinal cohort of youth who were followed from middle school and junior high school (ages 12-13) through high school or were high school dropouts (ages 17-18), we propose three studies: a) to examine the strongest determinants of youth smoking behavior, and whether these constructs are better interpreted within a single theoretical paradigm or within a more parsimonious construction of social influence theory; 2) to identify if there are special factors that should be considered to tailor prevention programing for high risk youth; and 3) to explore the temporal relationships between emotional distress and smoking risk, as well as the potential moderating effect of social bonding on this relationship, for adolescents. Collectively, these three studies will better inform our understanding of tobacco use risks and influences among adolescents. This work will provide information for populations that are easy to reach through school-based interventions, as well as for those who are difficult to study and are at particularly high risk, high school dropouts.